This application requests partial support from the National Institute for Environmental Health Sciences (NIEHS) for an international symposium entitled BENZENE 2009: Health effects, Mechanisms of Toxicity, Implications for t-AML and Application of the Mode of Action Framework, which will be held at the Technical University of Munich, Germany, September 7-11, 2009. Since its inception the NIEHS has been concerned with benzene because of both its occupational and its environmental toxicity. This symposium will devote its discussion to new findings on the mechanism of benzene-induced bone marrow damage. Benzene is a bone marrow toxin and carcinogen (leukemia) and despite attempts to control exposure in more highly developed countries in Europe and in the US, excessive benzene exposure persists in China and other areas of Asia. Reports have been invited on recent epidemiological studies of benzene-induced bone marrow damage. The investigators will explore advances in benzene-related bone marrow patho-physiology, mechanisms of leukemogenesis;the similarities between benzene-induced leukemia and anticancer treatment related leukemia;recent studies on the effects of benzene on the molecular biology of the bone marrow;benzene exposure;biomarkers such as chromosome damage;and risk assessment. They will make use of the Mode of Action framework when evaluating recent data on benzene and suggest data gaps which when filled will enhance the process of risk assessment. A panel discussion will deal with the issues raised at the meeting and special attention will be paid to the question of the adequacy of current occupational standards to protect workers. Speakers from 13 countries have been invited and special arrangements are being made to bring students from underdeveloped countries to participate. The proceedings will be published as a special issue of Chemico-Biological Interactions. The Symposium will explore recent advances in benzene-related bone marrow patho-physiology, mechanisms of leukemogenesis, epidemiology of benzene-induced bone marrow damage, recent studies on the effects of benzene on the molecular biology of the bone marrow, benzene exposure and biomarkers and risk assessment. The primary interests of NIEHS is in the environmental impacts of exposure to benzene and in fundamental mechanisms of benzene toxicity and how these data can be utilized in benzene risk assessment. Much of the discussion will relate directly to interests of the NIEHS.